Distribution and source of 129I, 239, 240Pu, 137Cs in the environment of Lithuania. (January 2016) - Ežerinskis, Ž.
Abstract: Fifty five soil samples collected in the Lithuania teritory in 2011 and 2012 were analyzed for 129 I, 137 Cs and Pu isotopes in order to investigate the level and distribution of artificial radioactivity in Lithuania. The activity and atomic ratio of 238 Pu/ 239, 24 0 Pu, 129 I/ 127 I and 131 I/ 137 Cs were used to identify the origin of these radionuclides. The 238 Pu/ 239+240 Pu and 240 Pu/ 239 Pu ratios in the soil samples analyzed varied in the range of 0.02–0.18 and 0.18–0.24, respectively, suggesting the global fallout as the major source of Pu in Lithuania. The values of 10 −9 to 10 −6 for 129 I/ 127 I atomic ratio revealed that the source of 129 I in Lithuania is global fallout in most cases though several sampling sites shows a possible impact of reprocessing releases. Estimated 129 I/ 131 I ratio in soil samples from the southern part of Lithuania shows negligible input of the Chernobyl fallout. No correlation of the 137 Cs and Pu isotopes with 129 I was observed, indicating their different sources terms. Results demonstrate uneven distribution of these radionuclides in the Lithuanian territory and several sources of contamination i.e. Chernobyl accident, reprocessing releases and global fallout. Highlights: The ratios radionuclides in soil samples show that there are two major sources. The 129 I/ 127 I atomic ratio in the soil samples range from 10 −9 to 10 −6 . The reconstructed 129 I/ 131 I in most cases shows the global fallout. The concentration of 137 Cs contrary to the 129 I did not increase over 30 years.